Battery case and battery pack

Abstract

This battery case comprises: an inner case including an inside gas exhaust hole via which gas generated by a battery accommodated in a battery accommodation chamber is expelled out of the battery accommodation chamber; an outer case that that has an inner-case-accommodating chamber for accommodating the inner case, and that includes an outside gas exhaust hole via which gas is expelled; a plurality of ribs that extend from the outer surface of the inner case to the inner surface of the outer case and position the inner case with respect to the outer case, the plurality of ribs being arranged at intervals from each other; and one or more gas guiding passages that are defined by the outer surface of the inner case, the inner surface of the outer case, and the plurality of ribs, and that guide the gas from the inside-gas-exhaust-hole side to the outside-gas-exhaust-hole side.

Description

[Technical Field]

[0001] The present disclosure relates to a battery case and a battery pack. [Background technology]

[0002] A conventional battery pack is described in Patent Document 1. This battery pack has a duct that circulates gas released from the battery when the battery generates abnormal heat. This battery pack lowers the temperature of the gas in the duct and discharges the cooled gas to the outside, thereby ensuring the safety of the area around the battery pack when the battery generates abnormal heat. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5378670 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery pack requires the installation of ducts throughout the battery pack, which tends to complicate the structure and increase the manufacturing costs.

[0005] Therefore, an object of the present disclosure is to provide a battery case and a battery pack that can not only efficiently cool gas released from a battery when the battery generates abnormal heat, but also has a simple structure and can reduce manufacturing costs. [Means for solving the problem]

[0006] In order to solve the above problems, the battery case of the present disclosure comprises an inner case having a battery housing chamber that houses multiple batteries and including an inner gas exhaust section that exhausts gas generated by the batteries housed in the battery housing chamber to the outside of the battery housing chamber; an outer case having an inner case housing chamber that houses the inner case and including an outer gas exhaust section that exhausts the gas to the outside; a plurality of inner case positioning sections that extend from the outer surface of the inner case to the inner surface of the outer case and position the inner case relative to the outer case, and are arranged at intervals from each other; and one or more gas guide passages that are defined by the outer surface of the inner case, the inner surface of the outer case, and the plurality of inner case positioning sections, and that guide gas from the inner gas exhaust section side to the outer gas exhaust section side.

[0007] The inner gas discharge portion may be configured as at least one of one or more inner holes and one or more inner breakable portions that break when the internal pressure of the battery housing chamber reaches or exceeds a first predetermined pressure. The outer gas discharge portion may be configured as at least one of one or more outer holes and one or more outer breakable portions that break when the internal pressure of the inner case housing chamber reaches or exceeds a second predetermined pressure. In such a configuration, the first predetermined pressure may be the same as the second predetermined pressure or may be different from the second predetermined pressure.

[0008] A battery pack according to the present disclosure includes the battery case according to the present disclosure and a plurality of batteries arranged in the battery housing chamber of the battery case. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to realize a battery case and a battery pack that can not only efficiently cool gas released from a battery when the battery generates abnormal heat, but also has a simple structure and can reduce manufacturing costs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view of a battery pack according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] Cross-sectional view of line BB in Figure 1 [Figure 4] 4 is a plan view of the inner case of the battery pack as viewed from one side in the height direction (thickness direction) indicated by arrow D in FIG. 3. FIG. [Figure 5] 3 is a cross-sectional view corresponding to FIG. 2 of a battery pack according to a modified example of the first embodiment. FIG. [Figure 6] 10 is a plan view corresponding to FIG. 4 of an inner case included in a battery pack according to a second embodiment. FIG. [Figure 7] 10 is a plan view corresponding to FIG. 4 of an inner case included in a battery pack according to a third embodiment. FIG. [Figure 8] 10 is a cross-sectional view corresponding to FIG. 2 of a battery pack according to a fourth embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that, when multiple embodiments or variations are included below, it is anticipated from the outset that new embodiments may be constructed by appropriately combining their characteristic features. Furthermore, the multiple drawings include schematic diagrams, and the dimensional ratios of the length, width, height, etc. of each component between different drawings do not necessarily match. Furthermore, among the components described below, components that are not recited in the independent claim representing the highest concept are optional components and are not required components. Furthermore, when the term "approximately" is used in this specification, it is used in the same sense as the term "approximately," and the requirement of "approximately" is met if the components are substantially the same.

[0012] In the following embodiments and modifications, the battery pack 1, 101, 401 will be described as having a generally rectangular parallelepiped shape. In the drawings and examples, the X direction indicates the longitudinal direction of the battery pack 1, 101, 401 (outer case 2, 102, 402), the Y direction indicates the width direction (short side direction) of the battery pack 1 (outer case 2, 102, 402), and the Z direction indicates the height direction (thickness direction) of the battery pack 1, 101, 401 (outer case 2, 102, 402). The X direction, Y direction, and Z direction are perpendicular to each other. In the following examples, the same components are denoted by the same reference numerals in the drawings, and redundant description will be omitted. In the modifications of the first embodiment and the second embodiment and subsequent embodiments, description of the same functions, effects, and modifications as those of the first embodiment will be omitted.

[0013] (First embodiment) FIG. 1 is a perspective view of a battery pack 1 according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1 (a cross-sectional view of the battery pack 1 cut along an XZ plane passing through the center in the Y direction). FIG. 3 is a cross-sectional view taken along line BB in FIG. 1 (a cross-sectional view of the battery pack 1 cut along the YZ plane at a location in the battery pack 1 that is neither the center nor an end in the X direction). As shown in FIG. 1, the battery pack 1 includes an outer case 2 having a substantially rectangular parallelepiped shape. The outer case 2 is made of, for example, a metal material or a resin material. The outer case 2 has one outer gas discharge hole 3 as an example of an outer gas discharge section at one end of the outer case 2 in the X direction. The battery pack 1 further includes a mesh-shaped discharge hole covering member 4 made of, for example, a metal or a resin. The discharge hole covering member 4 is fixed to the outer case 2 by a fixing means, for example, an adhesive or a welded portion, so as to close the outer gas discharge hole 3. The exhaust hole covering member 4 does not have to be mesh-shaped, and may be made of a breathable, waterproof material that allows exhaust gas to pass through but blocks liquids such as water from the outside, such as Gore-Tex (registered trademark).

[0014] 2, the battery pack 1 further includes an inner case 5, a block-shaped positioning member 6 made of an elastic material such as rubber, and a plurality of cylindrical secondary batteries (hereinafter simply referred to as batteries) 7 as an example of a plurality of batteries. The battery pack 1 includes a battery case 8 and the plurality of batteries 7, and the battery case 8 includes the inner case 5, the outer case 2, the discharge hole covering member 4, and the positioning member 6.

[0015] Although the battery 7 in this embodiment is a typical secondary battery, such as a lithium ion battery, a lithium secondary battery, a nickel-cadmium battery, or a nickel-metal hydride battery, the battery provided in the battery pack of the present disclosure may be a primary battery, such as a manganese battery or an alkaline battery. Furthermore, the battery provided in the battery pack of the present disclosure is not limited to a primary battery or a secondary battery, and may not be a cylindrical battery, but may be, for example, a prismatic battery or a pouch-type battery.

[0016] The inner case 5 has a battery chamber 11 that houses multiple batteries 7. The inner case 5 has an inner case main body 5a and a flat lid portion 5b. The inner case main body 5a has a first recess 11a that houses multiple batteries 7 with their axial directions aligned, and has an opening only on the other side in the X direction (one side in the axial direction of the batteries 7). After the multiple batteries 7 are housed in the first recess 11a of the inner case main body 5a, the lid portion 5b is fixed to the end of the inner case main body 5a on the other side in the X direction with a fixing means, for example, a fastening member such as a screw (not shown), so as to close the opening on the other side in the X direction of the inner case main body 5a. The lid portion 5b may also be formed integrally with the inner case main body 5a. In this case, the inner case main body 5a is constructed by dividing it into multiple components, and the inner case main body 5a is assembled after the multiple batteries 7 are housed.

[0017] The battery accommodating chamber 11 is thus defined by the inner case body 5a and the lid portion 5b. The inner case body 5a may have a battery holder, and the battery 7 may be accommodated in the battery holder. Alternatively, the battery 7 may be fixed to the inner surface of the first recess 11a of the inner case body 5a with double-sided tape or adhesive. The lid portion 5b has one inner gas exhaust hole 12 as an example of an inner gas exhaust portion. The inner gas exhaust hole 12 extends in the X direction (the axial direction of the battery 7) and penetrates the lid portion 5b. The inner gas exhaust hole 12 is provided to exhaust gas generated when the battery 7 fixed in the battery accommodating chamber 11 generates abnormal heat to the outside of the battery accommodating chamber 11.

[0018] The inner case 5 is housed in an inner case storage chamber 14 provided within the outer case 2. Specifically, the outer case 2 has an outer case main body 2a and a flat lid portion 2b. The outer case main body 2a has a second recess 14a that houses the inner case 5 and has an opening on only one side in the X direction (the other side in the axial direction of the battery 7). The outer case main body 2a has multiple inner case locking pieces 2c on one side in the X direction of the outer case main body 2a that protrude into the inner case storage chamber 14 in a direction perpendicular to the X direction (Z direction). The multiple inner case locking pieces 2c are located at intervals in the X direction relative to an inner surface 13 on one side in the X direction of the outer case main body 2a. The multiple inner case locking pieces 2c have a flat plate shape and are located at intervals from one another. End faces 16 on the other side in the X direction of the multiple inner case locking pieces 2c are located approximately flush with each other in the YZ plane formed by the Y and Z directions.

[0019] The inner case 5, which includes a lid portion 5b fixed to an inner case body 5a and contains multiple batteries 7, is moved relative to the outer case body 2a in one direction in the X direction, as indicated by arrow C in FIG. 2, until the inner case 5's end face on one side in the X direction abuts the inner case locking piece 2c. The block-shaped positioning member 6 is then pushed into the second recess 14a until it abuts the inner case 5's end face on the other side in the X direction. The lid portion 2b is then fixed to the outer case body 2a using a fastening member (not shown), such as a screw, to close the opening of the second recess 14a. By pushing the positioning member 6 in one direction in the X direction when fixing the lid portion 2b to the outer case body 2a, the inner case 5 can be precisely positioned relative to the outer case 2 in the X direction.

[0020] As shown in FIG. 3 , the inner case 5 has a plurality of ribs 15 that extend from its outer surface to the inner surface of the outer case 2 and position the inner case 5 relative to the outer case 2. The ribs 15 include one or more first ribs 15a that extend in the height direction (Z direction) of the battery pack 1 and contact the inner surface of the outer case 2 on one side in the Z direction, and one or more second ribs 15b that extend in the Z direction and contact the inner surface of the outer case 2 on the other side in the Z direction. The ribs 15 also include one or more third ribs 15c that extend in the Y direction and contact the inner surface of the outer case 2 on one side in the Y direction, and one or more fourth ribs 15d that extend in the Y direction and contact the inner surface of the outer case 2 on the other side in the Y direction. This allows for precise positioning of the inner case 5 relative to the outer case 2 in the Y and Z directions, resulting in precise positioning of the inner case 5 relative to the outer case 2. Each rib 15 constitutes an inner case positioning portion.

[0021] Although not described in detail, the inner case 5 is made of an insulating material such as resin, and one or more partially conductive metal parts are fixed to the inner case 5. The batteries 7 are electrically connected in at least one of series and parallel connections by the one or more metal parts while fixed in predetermined positions in the inner case 5. The existence of a series connection allows the output of the battery pack 1 to be increased, and the existence of a parallel connection allows the capacity of the battery pack 1 to be increased.

[0022] Fig. 4 is a plan view of the inner case 5 as viewed from one side in the Z direction indicated by arrow D in Fig. 3. As shown in Fig. 4, each rib 15 extends in the X direction from one end to the other end of the inner case 5 in the X direction. As shown in Fig. 3, between each pair of ribs 15 adjacent in the circumferential direction on the outer peripheral surface of the inner case 5, there exists a gas guide passage 18 extending in the X direction, which is defined by the two ribs 15, 15, the outer surface of the inner case 5, and the inner surface of the outer case 2.

[0023] 2 again, each inner case locking piece 2c is configured to block only a portion of the opening on one side in the X direction of the gas guide passage 18 (see FIG. 3), and the positioning member 6 is configured to block only a portion of the opening on the other side in the X direction of the gas guide passage 18. Therefore, the battery accommodating chamber 11, the space 19 formed in the X direction between the lid portion 5b of the inner case 5 and the lid portion 2b of the outer case 2, each gas guide passage 18, the space 20 formed in the X direction between the end face on one side in the X direction of the inner case 5 and the inner surface on one side in the X direction of the outer case 2, and the space outside the battery pack 1 are all in communication with each other due to the presence of the inner gas discharge hole 12 and the outer gas discharge hole 3.

[0024] In the above configuration, if at least one battery 7 generates abnormal heat and emits high-temperature gas to the outside, the high-temperature gas flows as follows. The high-temperature gas passes through the inner gas exhaust hole 12 on the other side of the inner case 5 in the X direction, which is the only part of the inner case 5 that communicates with the outside, and reaches the space 19. It then flows through one of the gas guide passages 18 to one side in the X direction and reaches the space 20. The temperature of the gas gradually decreases as it flows through the gas guide passage 18 to one side in the X direction. The gas that reaches the space 20 passes through the outer gas exhaust hole 3 and the mesh-like exhaust hole covering member 4. The gas is cooled more efficiently by coming into contact with the exhaust hole covering member 4. After passing through the outer gas exhaust hole 3 and the mesh-like exhaust hole covering member 4, the gas is discharged to the outside of the battery pack 1.

[0025] As described above, the battery case 8 comprises: an inner case 5 having a battery storage chamber 11 that stores multiple batteries 7 and including inner gas exhaust holes (inner gas exhaust sections) 12 that exhaust gas generated by the batteries 7 stored (e.g., fixed) in the battery storage chamber 11 to the outside of the battery storage chamber 11; an outer case 2 having an inner case storage chamber 14 that stores the inner case 5 and including outer gas exhaust holes (outer gas exhaust sections) 3 that exhaust gas to the outside; a plurality of ribs (inner case positioning sections) 15 that extend from the outer surface of the inner case 5 to the inner surface of the outer case 2 to position the inner case 5 relative to the outer case 2 and are arranged at intervals from each other; and one or more gas guide passages 18 that are defined by the outer surface of the inner case 5, the inner surface of the outer case 2, and the plurality of ribs 15 and that guide gas from the inner gas exhaust hole 12 side to the outer gas exhaust hole 3 side.

[0026] According to the present disclosure, a long gas exhaust path can be formed by effectively using the space between the inner case 5 and the outer case 2. This allows the temperature of the gas emitted from the battery 7 to be efficiently reduced, improving safety when the battery 7 abnormally heats up. Furthermore, according to the present disclosure, by simply providing an inner case positioning portion that positions the inner case 5 relative to the outer case 2, there is no need to lay complex piping, and the gas guide path 18 can be configured with an extremely simple structure. Therefore, gas released from the battery 7 when the battery abnormally heats up can be cooled with a simple structure at low cost.

[0027] Furthermore, the multiple inner case positioning portions may include multiple ribs 15 .

[0028] According to this configuration, the desired gas guide passage 18 can be formed simply and inexpensively by adjusting the formation positions of adjacent ribs 15. In addition, a gas guide passage 18 having a long path length and a high gas cooling effect can be formed.

[0029] The battery accommodating chamber 11 may be configured to accommodate multiple cylindrical batteries 7. The outer case 2 may have outer gas discharge holes 3 only at one end in the height direction (axial direction, coinciding with the X direction) of the cylindrical batteries 7 accommodated and fixed in the battery accommodating chamber 11, while the inner case 5 may have inner gas discharge holes 12 only at the other end in the X direction.

[0030] According to this configuration, the length of the gas guide passage 18 in the X direction can be increased, thereby improving the gas cooling effect. In the first embodiment, the outer gas discharge hole (outer gas discharge portion) 3 is formed in the end face on one axial side, but the outer gas discharge portion may be formed in the outer peripheral surface portion on one axial side of the outer case. Also, the inner gas discharge hole (inner gas discharge portion) 12 is formed in the end face on the other axial side, but the inner gas discharge portion may be formed in the outer peripheral surface portion on the other axial side of the inner case.

[0031] Furthermore, the inner case 5 and the plurality of ribs (inner case positioning portions) 15 may be integrally formed from an insulating material.

[0032] According to this configuration, the battery pack 1 can be easily assembled.

[0033] The battery case 8 may also include a mesh-like exhaust hole covering member 4 that covers the outer gas exhaust hole 3. The exhaust hole covering member 4 is preferably made of a metal mesh or porous metal. Alternatively, the battery case may be made of an air-permeable, waterproof material that allows gas emitted by the battery 7 to pass through while preventing external water from penetrating into the outer case when the battery 7 generates abnormal heat, and may also include an air-permeable, waterproof member that covers the outer gas exhaust section. In this case, the air-permeable, waterproof member is burned by the gas emitted by the battery, and the gas is discharged from the outer gas exhaust section to the outside of the battery pack.

[0034] According to this configuration, the gas can also be cooled by the discharge hole covering member 4, thereby improving safety.

[0035] In the first embodiment, the inner case 5 and a plurality of inner case positioning portions (e.g., ribs 15) are integrally molded. However, as shown in FIG. 5, i.e., a cross-sectional view of a modified battery pack 101 corresponding to FIG. 2, the inner case positioning portions (e.g., ribs 115) may be integrally molded with the outer case 102 rather than with the inner case 105. Alternatively, the inner case positioning portions may be formed as separate annular members distinct from the inner case and the outer case, and the inner case positioning portions formed as annular members may be inserted between the outer peripheral surface of the inner case and the inner peripheral surface of the outer case. In this case, it is preferable to form the inner case positioning portions from an elastic material, such as a rubber material or an elastic metal material, to facilitate assembly.

[0036] 2 and 3, in the first embodiment, the plurality of batteries 7 are arranged in two rows and two columns inside the inner case 5, but in the battery pack of the present disclosure, the plurality of batteries may be arranged in N rows and M columns (here, N and M are both natural numbers, but at least one of N and M is an integer of 2 or more). In the first embodiment, the outer gas discharge hole 3 is covered with a mesh-like discharge hole covering member 4, but the outer gas discharge hole does not have to be covered with a mesh-like discharge hole covering member.

[0037] In the first embodiment, the outer gas exhaust section is composed of one outer gas exhaust hole 3 and the inner gas exhaust section is composed of one inner gas exhaust hole 12, but the outer gas exhaust section may be composed of two or more outer gas exhaust holes, and the inner gas exhaust section may be composed of two or more inner gas exhaust holes. Alternatively, for safety reasons, secondary batteries have conventionally been structured so as to be destroyed when the internal pressure exceeds a predetermined pressure, thereby discharging generated gases and the like to the outside. Similarly, at least one of the inner gas exhaust section and the outer gas exhaust section may be structured so as to be destroyed when the internal pressure exceeds a predetermined pressure, and such a structure may be, for example, a portion having lower strength (rigidity) than other portions.

[0038] (Second embodiment) FIG. 6 is a plan view corresponding to FIG. 4 of an inner case 205 included in a battery pack of a second embodiment. The second embodiment differs from the first embodiment only in the shape (structure) of the rib 215 of the inner case 205; all other configurations of the second embodiment are the same as those of the first embodiment. As shown in FIG. 6, in the inner case 205, a gas guide passage 218 is located between two adjacent ribs 215 spaced apart. When the gas flow direction is from the inner gas discharge hole 12 side (see FIG. 2) toward the outer gas discharge hole 3 (see FIG. 2), at least one rib 215 has one protruding portion 217 and a plurality of protrusions 219 that protrude from the protruding portion 217 and move away from the protruding portion 217 toward the downstream side of the gas flow. The protrusions 219 are spaced apart from one another.

[0039] According to the second embodiment, the gas can be made to flow along a meandering path as shown by arrow E in Fig. 6, and the length of the path the gas takes to be discharged to the outside can be increased, thereby further improving the cooling effect of the gas.

[0040] Furthermore, protrusions 219 protrude from protrusion 217 so as to move away from protrusion 217 toward the downstream side of the gas flow. In other words, protrusions 219 protrude from protrusion 217 toward the downstream side of the gas flow as they move from the base on the protrusion 217 side toward the tip. Therefore, protrusions 219 do not obstruct the flow of gas toward the downstream side, and the gas can flow smoothly toward the downstream side.

[0041] (Third embodiment) 7 is a plan view corresponding to FIG. 4 of an inner case 305 included in a battery pack of a third embodiment. In the third embodiment, only the shape (structure) of the inner case positioning portion of the inner case 305 is different from that of the first embodiment, and all other configurations of the third embodiment are the same as those of the first embodiment. As shown in FIG. 7, in the third embodiment, the multiple inner case positioning portions include multiple columnar protrusions 315 arranged at intervals from each other. The protrusions 315 may be, for example, boss-shaped (cylindrical) or rectangular-prism-shaped.

[0042] According to the third embodiment, the gas can be agitated and turbulent flow can be generated by the plurality of columnar protrusions 315. Therefore, the gas can be cooled more effectively.

[0043] (Fourth embodiment) 8 is a cross-sectional view of a battery pack 401 according to a fourth embodiment, corresponding to FIG. 2. The battery pack 401 differs from the battery pack 1 only in two configurations, which will be described below. Specifically, the battery pack 401 differs from the battery pack 1 in that the battery pack 401 has inner gas exhaust holes 477, 478, which serve as an example of an inner gas exhaust portion, at one end and the other end in the height direction (corresponding to the X direction) of the cylindrical battery 7, in which the inner case 405 is fixed to the battery housing chamber 411. The battery pack 401 also differs from the battery pack 1 in that the outer case 402 has outer gas exhaust holes 487, 488, which serve as an example of an outer gas exhaust portion, in the center, which is located other than both end portions in the X direction.

[0044] Outer gas exhaust hole 487 is provided at one end of outer case 402 in the Z direction, and communicates with all gas guide passages (not shown) located on one side in the Z direction. In addition, outer gas exhaust hole 488 is provided at the other end of outer case 402 in the Z direction, and communicates with all gas guide passages (not shown) located on the other side in the Z direction.

[0045] Depending on the specifications of the battery pack, a large number of batteries may be connected in series, resulting in a long height dimension of the cylindrical batteries 7 in the battery pack. In such a case, even if the configuration of the fourth embodiment is adopted, it is possible to form a gas guide passage with a path length sufficient for cooling the gas.

[0046] 6 is formed on the rib, the gas flow direction in the gas guide passage located on one side in the X direction will be opposite to that in the gas guide passage located on the other side in the X direction. Therefore, the multiple protrusions are formed so that the inclination direction (inclination direction) of the protrusions is different on one side in the X direction and the other side in the X direction, with the formation positions of the outer gas discharge holes 487, 488 in the X direction as the boundary.

[0047] (Other variations) The present disclosure is not limited to the above-described embodiment and its modifications, and various improvements and modifications are possible within the scope of the claims of the present application and their equivalents.

[0048] For example, the inner case positioning portion may include both the plurality of ribs 15 described with reference to FIGS. 3 and 4 and the plurality of protrusions 315 described with reference to FIG.

[0049] Also, the case where the outer case 2 has a rectangular parallelepiped shape has been described. However, the outer case of the present disclosure does not have to have a rectangular parallelepiped shape and may have any shape as long as it can have an inner case housing chamber and an outer gas exhaust portion. Similarly, the inner case of the present disclosure may have any shape as long as it can have a battery housing chamber and an inner gas exhaust portion.

[0050] In the above description, the battery pack 1, 101, 401 has a generally rectangular parallelepiped appearance, and the gas guide passage 18 extends in the X direction (longitudinal direction) or along a zigzag path along the X direction. However, the gas guide passage may extend in the width direction of the battery pack or along a zigzag path along the width direction. Alternatively, the gas guide passage may include a portion extending along the longitudinal direction of the battery pack and a portion extending along the width direction. Alternatively, the gas guide passage may include a portion extending in a direction inclined at an acute angle to the longitudinal direction of the battery pack. For example, the gas guide passage may extend along the diagonal line of the battery pack in the XY plane. The battery case of the present disclosure may also have a spiral rib. Providing such a spiral rib significantly increases the path length of the gas guide passage, even in a compact battery case, thereby improving gas cooling performance. [Explanation of symbols]

[0051] 1,101,401 Battery pack, 2,102,402 Outer case, 3,487,488 Outer gas exhaust hole, 4 Exhaust hole covering member, 5,105,205,305,405 Inner case, 7 Battery, 8 Battery case, 11,411 Battery storage chamber, 12,477,478 Inner gas exhaust hole, 14 Inner case storage chamber, 15,15a,15b,15c,15d,115,215 Rib, 18,218 Gas guide passage, 217 Protrusion, 219 Protrusion, 315 Protruding portion.

Claims

1. an inner case having a battery accommodating chamber for accommodating a plurality of batteries, the inner case including an inner gas exhaust portion for exhausting gas generated by the batteries accommodated in the battery accommodating chamber to the outside of the battery accommodating chamber; an outer case having an inner case accommodating chamber for accommodating the inner case and including an outer gas exhaust portion for exhausting the gas to the outside; a plurality of inner case positioning portions extending from an outer surface of the inner case to an inner surface of the outer case to position the inner case relative to the outer case, the inner case positioning portions being spaced apart from one another; one or more gas guide passages defined by an outer surface of the inner case, an inner surface of the outer case, and the plurality of inner case positioning portions, and which guide gas from the inner gas discharge portion side to the outer gas discharge portion side; Equipped with the plurality of inner case positioning portions include a plurality of ribs, the gas guide passage is located between two adjacent ribs spaced apart, a battery case in which, when a direction from the inner gas discharge section toward the outer gas discharge section is defined as a gas flow direction, at least one of the ribs has one protrusion portion and a plurality of protrusions that protrude from the protrusion portion so as to move away from the protrusion portion toward the downstream side of the gas flow and are positioned at intervals from each other.

2. an inner case having a battery accommodating chamber for accommodating a plurality of batteries, the inner case including an inner gas exhaust portion for exhausting gas generated by the batteries accommodated in the battery accommodating chamber to the outside of the battery accommodating chamber; an outer case having an inner case accommodating chamber for accommodating the inner case and including an outer gas exhaust portion for exhausting the gas to the outside; a plurality of inner case positioning portions extending from an outer surface of the inner case to an inner surface of the outer case to position the inner case relative to the outer case, the inner case positioning portions being spaced apart from one another; one or more gas guide passages defined by an outer surface of the inner case, an inner surface of the outer case, and the plurality of inner case positioning portions, and which guide gas from the inner gas discharge portion side to the outer gas discharge portion side; Equipped with The battery chamber is adapted to accommodate a plurality of cylindrical batteries, A battery case in which the outer case has the outer gas exhaust portion only at one end in the height direction of the cylindrical battery housed in the battery housing chamber, while the inner case has the inner gas exhaust portion only at the other end in the height direction.

3. The battery case according to claim 2 , wherein the plurality of inner case positioning portions include a plurality of ribs.

4. The battery case according to claim 1 , wherein the plurality of inner case positioning portions include a plurality of columnar protrusions arranged at intervals from one another.

5. The battery chamber is adapted to accommodate a plurality of cylindrical batteries, 2. The battery case according to claim 1, wherein the inner case has the inner gas exhaust portion at one end and the other end in the height direction of the cylindrical battery housed in the battery housing chamber, while the outer case has the outer gas exhaust portion in a central portion located other than both end portions in the height direction.

6. The battery case according to claim 1 , wherein the inner case and the plurality of inner case positioning portions are integrally formed from an insulating material.

7. 7. The battery case according to claim 1, further comprising a mesh-like member covering the outer gas exhaust portion, or a breathable and waterproof member covering the outer gas exhaust portion, which is made of a breathable and waterproof material that allows the gas to pass through while preventing external water from penetrating into the outer case.

8. The battery case according to any one of claims 1 to 7; the plurality of batteries disposed in the battery accommodating chamber of the battery case; A battery pack comprising:

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